On 21/10/2023 19:14, Jason Gunthorpe wrote:
On Fri, Oct 20, 2023 at 03:43:57PM +0100, Joao Martins wrote:
On 20/10/2023 00:59, Jason Gunthorpe wrote:
On Thu, Oct 19, 2023 at 12:58:29PM +0100, Joao Martins wrote:
AMD has no such behaviour, though that driver per your earlier suggestion might
need to wait until -rc1 for some of the refactorings get merged. Hopefully we
don't need to wait for the last 3 series of AMD Driver refactoring (?) to be
done as that looks to be more SVA related; Unless there's something more
specific you are looking for prior to introducing AMD's domain_alloc_user().
I don't think we need to wait, it just needs to go on the cleaning list.
I am not sure I followed. This suggests an post-merge cleanups, which goes in
different direction of your original comment? But maybe I am just not parsing it
right (sorry, just confused)
Yes post merge for the weirdo alloc flow
for themselves; so more and more I need to work on something like
iommufd_log_perf tool under tools/testing that is similar to the gup_perf to make all
performance work obvious and 'standardized'
We have a mlx5 vfio driver in rdma-core and I have been thinking it
would be a nice basis for building an iommufd tester/benchmarker as it
has a wide set of "easilly" triggered functionality.
Oh woah, that's quite awesome; I'll take a closer look; I thought rdma-core
support for mlx5-vfio was to do direct usage of the firmware interface, but it
appears to be for regular RDMA apps as well. I do use some RDMA to exercise
iommu dirty tracking; but it's more like a rudimentary test inside the guest,
not something self-contained.
I can't remember anymore how much is supported, but supporting more is
not hard work. With a simple QP/CQ you can do all sorts of interesting
DMA.
Yishai would remember if QP/CQ got fully wired up
For now, QP/CQ are supported only over the DEVX API (i.e.
mlx5dv_devx_obj_create()) of the mlx5-vfio driver in rdma-core.
In that case, data-path for RDMA applications should be done by the
application itself based on the mlx5 specification.
Yishai
Jason
